Article with electrically-conductive silver connector wire pattern

ABSTRACT

Electrically-conductive articles are prepared to have electrically-conductive silver metal electrode grids and electrically-conductive silver connector wire patterns (BUS lines) on one or both supporting sides of a transparent substrate. The electrically-conductive silver connector wire patterns are designed with at least one silver main wire that comprises two or more adjacent silver micro-wires in bundled patterns. These bundled patterns and silver micro-wires are designed with specific dimensions and configurations to provide optimal fidelity (or correspondence) to the mask image used to provide such images in a silver halide emulsion layer. The electrically-conductive articles are provided by imagewise exposure, development, and fixing of corresponding silver halide-containing conductive film element precursors containing photosensitive silver halide emulsion layers. The electrically-conductive articles can be used are parts of various electronic devices including touch screen devices.

RELATED APPLICATIONS

Reference is made to the following copending and commonly assignedpatent applications, the disclosures of all of which are incorporatedherein by reference:

U.S. Ser. No. 13/751,430 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok);

U.S. Ser. No. 13/751,443 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok), now issued as U.S. Pat. No. 9,167,688 on Oct. 20, 2015;

U.S. Ser. No. 13/751,464 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok), now issued as U.S. Pat. No. 9,005,744 on Apr. 14, 2015;

U.S. Ser. No. 13/751,450 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok), now issued as U.S. Pat. No. 9,137,893 on Sep. 15, 2015;

U.S. Ser. No. 13/964,453 (filed Aug. 12, 2013 by Lebens and Cok), nowissued as U.S. Pat. No. 9,131,606 on Sep. 8, 2015;

U.S. Ser. No. 14/166,910 (filed Jan. 29, 2014 by Kenneth Lushington),now issued as U.S. Pat. No. 9,247,640 on Jan. 26, 2016;

U.S. Ser. No. 14/281,925 (filed on May 20, 2014, by Lushington, Sutton,and Cok, and issued as U.S. Pat. No. 9,235,130 on Jan. 12, 2016)entitled “Method for Preparing Transparent Electrically-ConductiveArticles;”

U.S. Ser. No. 14/281,953 (filed on May 20, 2014, by Cok, Sutton, andLushington, and published as U.S. 2015/0338970 on Nov. 26, 2015)entitled “Electrically Conductive Article with Improved BUS Region;”

U.S. Ser. No. 14/281,968 (filed on May 20, 2014 by Youngblood and Lowe,and published as U.S. 2015/0338740 on Nov. 26, 2015) entitled “Methodfor Providing Conductive Silver Film Elements;”

U.S. Ser. No. 14/281,977 (filed on May 20, 2014, by Youngblood and Lowe,and published as U.S. 2015/0338741 on Nov. 26, 2015) entitled “SilverHalide Developing Solution;” and

U.S. Ser. No. 14/281,984 (filed on May 20, 2014, by Youngblood and Lowe,and published as U.S. 2015/0338742 on Nov. 26, 2015) entitled “SilverHalide Solution Physical Developing Solution.”

FIELD OF THE INVENTION

This invention relates to generally transparent electrically-conductivearticles having electrically-conductive silver electrode grids andelectrically-conductive silver connector wire patterns, whichelectrically-conductive articles are prepared from conductive filmelement precursors that have a photosensitive silver halide emulsionlayer on one or both sides of a transparent substrate. Theelectrically-conductive articles have specifically arrangedelectrically-conductive silver metal (fine wire) grids in a touch regionand electrically-conductive silver wire connector wire patterns on oneor both sides of the transparent substrate. This invention also relatesto devices such as touch screen panels into which theseelectrically-conductive articles can be incorporated.

BACKGROUND OF THE INVENTION

Rapid advances are occurring in various electronic devices especiallydisplay devices that are used for various communicational, financial,and archival purposes. For such uses as touch screen panels,electrochromic devices, light-emitting diodes, field-effect transistors,and liquid-crystal displays, conductive films are essential andconsiderable efforts are being made in the industry to improve theproperties of those conductive films and particularly to improve metalgrid or line conductivity and to provide as much correspondence betweenmask design with resulting user metal patterns.

Electrically-conductive articles used in various electronic devicesincluding touch screens in electronic, optical, sensory, and diagnosticdevices including but not limited to telephones, computing devices, andother display devices have been designed to respond to touch by a humanfingertip or mechanical stylus.

There is a particular need to provide touch screen displays and devicesthat contain improved conductive film elements. Currently, touch screendisplays use Indium Tin Oxide (ITO) coatings to create arrays ofcapacitive areas used to distinguish multiple points of contacts. ITOcoatings have significant disadvantages and efforts are being made toreplace their use in various electronic devices.

Silver is an ideal conductor having an electrical conductivity 50 to 100times greater than ITO and is being explored for this purpose. Unlikemost metal oxides, silver oxide is still reasonably conductive and thisreduces the problem of making reliable electrical connections. Silver isused in many commercial applications and is available from numeroussources. It is highly desirable to make conductive film elements usingsilver as the source of conductivity, but it requires considerabledevelopment to obtain optimal properties.

In known printed circuit board (PCB) and integrated circuit manufactureprocesses, the preferred means for mass manufacture is to print acircuit directly from a master article onto a suitable substrate, tocreate a copy of the circuit image on a suitable PCB photosensitivefilm, or to directly laser-write a master circuit image (or inversepattern) onto the PCB photosensitive film. The imaged PCB photosensitivefilm is then used as a “mask” for imaging multiple copies onto one ormore photoresist-coated substrates.

An essential feature of these methods is that the PCB photosensitivefilm and photoresist compositions are optimized in formulation anddevelopment so that the imaged copies are as faithful a representationof the master image as possible with respect to circuit dimensions andproperties. This property is sometimes referred to as “fidelity” (or“correspondence”) and the worse the fidelity, the poorer the performanceof the resulting copies. However, in mass production of these electricalcircuits having designed patterns with very fine dimensional features,there are a number of compositional and operational (for example,chemical processing) conditions that naturally work against fidelity, ormaking faithful reproductions of the master circuit image.

This is particularly true when silver halide is used for making themultiple copies of a master circuit pattern intended for use astransparent conductor patterns. For example, development of exposedsilver halide using strong developers intended to achieve highconductivity, and the high level of silver in the photosensitivecoatings for the same purpose, can lead to very large dimensionaldifferences between the master circuit image and copies made thereofusing various mask elements. In addition, this lack of faithfulreproduction of the dimensions in the master circuit image is stronglyinfluenced by the dimensional scale of the circuitry images that arebeing reproduced. Thus, smaller features in the master circuit imagebecome larger and the larger features in the master circuit image becomesmaller. These objectionable changes in the features from “master tocopy” result in reduced conductivity in the resulting copy patterns andoverall poorer performance in the electrical devices in which they areincorporated.

It requires considerable research and development effort to determinethe various causes of the lack of fidelity between master circuit imageand copies, especially when photosensitive silver halide is used forthis process. There are numerous publications relating to usingphotosensitive silver halide in this manner, but none that addresses thenoted problem.

For example, U.S. Patent Application Publication 2011/0308846 (Ichiki)describes the preparation of electrically-conductive films formed byreducing a silver halide image to form electrically-conductive networkswith silver wire sizes less than 10 μm, which electrically-conductivefilms can be used to form touch panels in displays. In addition,improvements have been proposed for providing electrically-conductivepatterns using photosensitive silver salt compositions such as silverhalide emulsions as described for example in U.S. Pat. No. 8,012,676(Yoshiki et al.).

Recently designed improved electrically-conductive articles are preparedfrom photosensitive silver halide precursor articles as described forexample in copending and commonly assigned U.S. Ser. No. 14/166,910(noted above).

Electrically-conductive silver articles have been described for use intouch screen panels that have electrically-conductive silver gridpatterns on both sides of a transparent substrate, for example as inU.S. Patent Application Publications 2011/0289771 (Kuriki) and2011/0308846 (noted above).

However, the mere presence of electrically-conductive silver gridpatterns on one or both sides of the transparent substrate is notsufficient to provide sufficient response that is needed for sensingtouch for various electronic devices. The conductive grid patterns mustbe connected in some manner to each other and to suitable electroniccomponents and software in the devices so that desired functions can beaccomplished in response to a touch from a finger or stylus. Thus, theelectrically-conductive articles are also designed with conductive “BUS”lines or electrically-conductive silver connecting wiring that isoutside the conductive electrode regions (“touch regions”) designed fortouching. In some embodiments, such electrically-conductive articleshave “sensitive regions” and “terminal wiring regions” on one or bothsides of the transparent substrate. One representation of such anelectrically-conductive article is shown in FIG. 8 of U.S. PatentApplication 2011/0289771 (noted above).

Normally, the conductive wiring in the electrically-conductive articleis not designed for high transparency or sensitivity to touch. Theconductive wiring will likely have different conductivity and dimensionscompared to the conductive grid patterns in what are known as the“sensitive regions” of the electrically-conductive article. Thesedifferences further make it harder to achieve desired fidelity of amaster circuit image and copies made therefrom.

Thus, there is a need for a means for providing transparentelectrically-conductive articles that have both electrically-conductivesilver grids in touch sensitive regions as well aselectrically-conductive silver wiring that are as close to beingreproductions to the master circuit image as possible. The presentinvention addresses these problems.

SUMMARY OF THE INVENTION

The present invention addresses these problems by providing anelectrically-conductive article using photosensitive silver halide andblack-and-white silver metal image-forming processing chemistry. Thiselectrically-conductive article comprises a transparent substrate havinga first supporting side and an opposing second supporting side,

the first supporting side comprising: (a) a electrically-conductivesilver metal electrode grid, (b) an electrically-conductive silverconnector wire pattern, and optionally, (c) transparent regions outsideof both the electrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern,

wherein:

(i) the electrically-conductive silver wire pattern comprises at leastone silver main wire that comprises two or more silver micro-wires thatare electrically connected to a silver end wire at an end of the leastone silver main wire, the two or more silver micro-wires and the silverend wire in the at least one silver main wire forming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1;

(iv) the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 68%; and

(v) for each silver micro-wire, the ratio of maximum height to minimumheight is at least 1.05:1.

In many embodiments, the electrically-conductive article furthercomprises on the opposing second supporting side: (a) an opposingelectrically-conductive silver metal electrode grid, (b) an opposingelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern,

wherein on the opposing second supporting side of the transparentsubstrate:

(i) the opposing electrically-conductive silver connector wire patterncomprises at least one silver main wire that comprises two or moresilver micro-wires that are electrically connected to a silver end wireat an end of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1;

(iv) the opposing electrically-conductive silver connector wire patternhas an integrated transmittance of less than 68%; and

(v) for each silver micro-wire, the ratio of maximum height to minimumheight is at least 1.05:1.

Other embodiments comprise an electrically-conductive article comprisinga transparent substrate having a first supporting side and an opposingsecond supporting side,

the first supporting side comprising: (a) a electrically-conductivesilver metal electrode grid, (b) an electrically-conductive silverconnector wire pattern, and optionally, (c) transparent regions outsideof both the electrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern,

wherein:

(i) the electrically-conductive silver connector wire pattern comprisesat least one silver main wire that comprises two or more silvermicro-wires that are electrically connected to a silver end wire at anend of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between any two adjacent silver micro-wires in eachbundled pattern is at least 0.5:1 but less than 2:1; and

(iv) the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 68%.

Such embodiments can further comprise on the opposing second supportingside of the transparent substrate: (a) an opposingelectrically-conductive silver metal electrode grid, (b) an opposingelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern,

wherein, on the opposing second supporting side of the transparentsubstrate:

(i) the opposing electrically-conductive silver connector wire patterncomprises at least one silver main wire that comprises two or moresilver micro-wires that are electrically connected to a silver end wireat an end of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1; and

(iv) the opposing electrically-conductive silver connector wire patternhas an integrated transmittance of less than 68%.

Still other useful embodiments comprise an electrically-conductivearticle comprising a transparent substrate having a first supportingside and an opposing second supporting side,

the first supporting side comprising: (a) a electrically-conductivesilver metal electrode grid, (b) an electrically-conductive silverconnector micro-wire pattern comprising at least one silver micro-wire,and optionally, (c) transparent regions outside of both theelectrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern,

wherein the ratio of maximum height to minimum height of the at leastone silver micro-wire is at least 1.05:1.

Such embodiments can further comprise on the opposing second supportingside of the transparent substrate: (a) an opposingelectrically-conductive silver metal electrode grid, (b) an opposingelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern,

wherein the ratio of maximum height to minimum height of the at leastone silver micro-wire on the opposing second supporting side of thetransparent substrate is at least 1.05:1.

The electrically-electrically-conductive articles of this invention areprovided using photosensitive black-and-white silver halide emulsionsand black-and-white silver metal image-forming processing chemistry, themethod comprising:

imagewise exposing a conductive film element precursor that comprises: atransparent substrate comprising a first supporting side and an opposingsecond supporting side; and a photosensitive silver halide emulsionlayer on at least the first supporting side, to radiation to provide, inthe photosensitive silver halide emulsion layer on at least the firstsupporting side: (a) a latent electrically-conductive silver metalelectrode grid, (b) a latent electrically-conductive silver connectorwire pattern different from the latent electrically-conductive silvermetal electrode grid, and optionally, (c) transparent regions outside ofboth the latent electrically-conductive silver metal electrode grid andthe latent electrically-conductive silver connector wire pattern; and

processing the latent silver metal electrode grid and the latentelectrically-conductive silver connector wire pattern using at leastsolution physical development and silver halide fixing, to provide: (a)a electrically-conductive silver metal electrode grid from the latentelectrically-conductive silver metal electrode grid, (b) anelectrically-conductive silver connector wire pattern from the latentelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the electrically-conductivesilver metal electrode grid and the electrically-conductive silverconnector wire pattern.

Some embodiments of this method comprise one or more of the followingfeatures:

(i) the electrically-conductive silver electrode wire pattern comprisesat least one silver main wire that comprises two or more silvermicro-wires electrically that are connected to a silver end wire at anend of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1;

(iv) the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 68%; and

(vi) for each silver micro-wire, the ratio of maximum height to minimumheight is at least 1.05:1.

In many embodiments of this method, the conductive film elementprecursor further comprises a photosensitive silver halide emulsionlayer disposed on the opposing second supporting side of the transparentsubstrate, and

the method further comprises:

imagewise exposing the photosensitive silver halide emulsion layer onthe opposing second supporting side to provide (a) an opposing latentelectrically-conductive silver metal electrode grid, (b) an opposinglatent electrically-conductive silver connector wire pattern differentfrom the opposing latent electrically-conductive silver metal electrodegrid, and optionally, (c) transparent regions outside of both theopposing latent electrically-conductive silver metal electrode grid andthe opposing latent electrically-conductive silver connector wirepattern; and

processing the opposing latent electrically-conductive silver metalelectrode grid and the opposing latent electrically-conductive silverconnector wire pattern using at least solution physical development andsilver halide fixing, to provide: (a) an opposingelectrically-conductive silver metal electrode grid from the opposinglatent electrically-conductive silver metal electrode grid, (b) anopposing electrically-conductive silver connector wire pattern from theopposing latent electrically-conductive silver connector wire pattern,and optionally, (c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern,

wherein:

(i) the opposing electrically-conductive silver connector wire patterncomprises at least one silver main wire that comprises two or moresilver micro-wires that are electrically connected to a silver end wireat an end of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1;

(iv) the opposing electrically-conductive silver connector wire patternhas an integrated transmittance of less than 68%; and

(vi) for each silver micro-wire, the ratio of maximum height to minimumheight is at least 1.05:1.

Thus, the method described herein provides an electrically-conductivearticle that has both electrically-conductive silver metal electrodegrids (for the “touch sensitive” or “touch” regions) andelectrically-conductive silver connector wire patterns (also identifiedas BUS lines, BUS regions, or simply electrode connector regions) withimproved matching (correspondence or fidelity) of the images of theseregions to the images in the original mask element through whichimagewise exposure occurs.

The advantages are achieved for the conductive silver wire patterns inthe electrode connector regions by arranging at least one silver mainwire (for example, two or more silver main wires) into bundled patternsof two or more silver micro-wires and various silver end wires for eachbundled pattern. In addition, adjacent silver micro-wires in the bundledpattern can be arranged with both electrically connecting silvercross-wires and silver end wires. The bundled patterns and silvermicro-wires are obtained from exposure and processing with specificdimensions, spacing, and conductive properties for optimal performancein touch screen devices. The bundled patterns of silver main wires andsilver micro-wires increase electrical conductivity, manufacturability,and robustness even in the presence of some manufacturing defects. Inother words, the possible effects of manufacturing defects orinconsistencies are at least reduced in the electrically-conductivearticles of the present invention.

Known methods for preparing electrically-conductive articles typicallycause the formation of continuous, solid, and substantially flatconductive lines and attempt to make maximum use of the available spaceon a transparent substrate. However, it has been found that the use ofsolution physical development with imagewise exposed silver halideemulsions does not readily allow the formation of such continuous,solid, and substantially flat conductive lines having desiredconductivity and lower resistance. Hence, known silver halide films andprocessing methods are not useful for this purpose, and would not teachor motivate a skilled worker to find and use the electrically-conductivearticles of the present invention. In particular, methods of the artthat employ silver halide development but do not include solutionphysical development, or which include known plating methods in whichthe deposited metals (or metal ions) come from an external source suchas a solution, can form continuous, solid, and flat conductive lines andtherefore do not suggest the electrically-conductive articles of thepresent invention.

In contrast to known methods, the electrically-conductive articles ofthe present invention exhibit improved electrical conductivity from thepresence of unique silver micro-wire bundled patterns. In one usefulembodiment, the silver-micro-wires have an average width of at least 5μm and up to and including 20 μm. Thus, the method described hereinprovides electrically-conductive articles having highlyelectrically-conductive silver connector wire patterns without requiringthe formation of continuous, solid, and substantially flat conductivelines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an electrically-conductive silverconnector wire pattern shown on one side of a transparent substrate,which electrically-conductive connector silver wire pattern can beincorporated into or part of an electrically-conductive article of thisinvention.

FIG. 2 is a schematic cross-sectional view of an electrically-conductivearticle according to the present invention.

FIG. 3A is a schematic cross-sectional view of a conductive film elementprecursor comprising a portion of a photosensitive silver halideemulsion layer disposed on a transparent substrate, which portion ofphotosensitive silver halide emulsion layer comprises non-developedphotosensitive silver halide grains.

FIG. 3B is a schematic cross-sectional view of a conductive film elementprecursor comprising developed photosensitive silver halide grains in arepresentative silver micro-wire disposed on a transparent substrate,which silver micro-wire can be obtained from the portion ofphotosensitive silver halide emulsion layer shown in FIG. 3A.

FIGS. 4 and 5 are schematic illustrations of electrically-conductivesilver connector wire patterns shown on one side of a transparentsubstrate, showing both silver end wires and different arrangements ofsilver cross-wires in multiple bundled patterns.

FIGS. 6 to 9 are flow charts showing options for formingelectrically-conductive articles from single-sided or duplex conductivefilm element precursors.

FIG. 10 is a schematic cross-sectional view of a silver micro-wire on atransparent substrate, which silver micro-wire has a maximum heightessentially at its center.

FIG. 11 is a schematic cross-sectional view of a silver micro-wire on atransparent substrate, which silver micro-wire has a maximum heightcloser to its outer edge than its center.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion is directed to various embodiments of thepresent invention and while some embodiments can be more desirable forspecific uses, the disclosed embodiments should not be interpreted orotherwise considered to be limiting the scope of the present invention,as claimed below. Thus, one skilled in the art should understand thatthe following disclosure and illustrative FIGS. have broader applicationthan is explicitly described and the discussion or illustration of anembodiment is not intended to limit the scope of the present invention.

Definitions

As used herein to define various components and structures of theconductive film element precursors including photosensitive silverhalide emulsion layers and processing solutions, unless otherwiseindicated, the singular forms “a,” “an,” and “the” are intended toinclude one or more of the components (that is, including pluralityreferents).

Each term that is not explicitly defined in the present application isto be understood to have a meaning that is commonly accepted by thoseskilled in the art. If the construction of a term would render itmeaningless or essentially meaningless in its context, the termdefinition should be taken from a standard dictionary.

The use of numerical values in the various ranges specified herein,unless otherwise expressly indicated otherwise, are considered to beapproximations as though the minimum and maximum values within thestated ranges were both preceded by the word “about.” In this manner,slight variations above and below the stated ranges can be used toachieve substantially the same results as the values within the ranges.In addition, the disclosure of these ranges is intended as a continuousrange including every value between the minimum and maximum values.

Unless otherwise indicated, the term “weight %” refers to the amount ofa component or material based on the total solids of a composition,formulation, solution, or the % of the dry weight of a layer. Unlessotherwise indicated, the percentages can be the same for either a drylayer or pattern, or for the total solids of the formulation orcomposition used to make that layer or pattern.

Unless otherwise indicated, the terms “conductive film elementprecursor” and “precursor” are meant to be the same thing and to referto an article used in the practice of the method of this invention toprovide a conductive film element (or electrically-conductive article)of the present invention. Such precursors therefore comprise a “silverprecursor material” (such as a silver halide) that can be converted toelectrically-conductive silver metal particles (for example byreduction). Much of the discussion about the precursors is equallyapplicable to the electrically-conductive articles as most of thecomponents and structure are not changed when silver cations areconverted to silver metal particles. Thus, unless otherwise indicated,the discussion of transparent substrates, hydrophilic binders andcolloids, and any other addenda in photosensitive silver halide emulsionlayers, any hydrophilic overcoats, and another other components orlayers for the precursors are also intended to describe the componentsof the resulting electrically-conductive articles.

Unless otherwise indicated, the terms “conductive film element” and“electrically-conductive article” are intended to mean the same thing.They refer to the materials containing the electrically-conductivesilver metal electrode grids and electrically-conductive silverconnector wire patterns disposed on either or both supporting sides of asuitable transparent substrate. Other components of theelectrically-conductive articles are described below.

The term “first” refers to the layers on one (first) supporting side ofthe transparent substrate and the term “second” refers to the layers onthe opposing (opposite) second supporting side of the transparentsubstrate. Each supporting side of the transparent substrate can beequally useful and the term “first” does not necessarily mean that oneside is the primary or better supporting side of the precursor orelectrically-conductive article.

The terms “duplex” and “two-sided” are used herein in reference toprecursors and electrically-conductive articles having the describedlayers and electrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns on bothsupporting sides of the transparent substrate. Unless otherwiseindicated herein, the relationships and compositions of the variouslayers can be the same or different on both supporting sides of thetransparent substrate.

ESD refers to “equivalent spherical diameter” and is a term used in thephotographic art to define the size of particles such as silver halidegrains. Particle size of silver halide grains as expressed in grain ESDcan be readily determined using disc centrifuge instrumentation.

Unless otherwise indicated, “black-and-white” refers to silver-formingblack-and-white materials and formulations, and not chromogenicblack-and-white materials and formulations.

In most embodiments, the conductive film element precursors and theresulting electrically-conductive articles, including the transparentsubstrate and all accompanying layers, electrically-conductive silvermetal electrode grids, and transparent regions on one or both supportingsides, are considered transparent meaning that its integratedtransmittance over the noted region of the electromagnetic spectrum (forexample from 410 nm to 700 nm) is 70% or more, or more likely at least85% or even 90% or more, as measured for example using aspectrophotometer and known techniques. Thus, the touch regions in theresulting electrically-conductive articles will have this highintegrated transmittance. However, the electrode connector regionscontaining the electrically-conductive silver connector wire patternsare generally much less transparent than the rest of theelectrically-conductive articles and generally have an integratedtransmittance of less than 68%, or less than 50%, or even less than 40%using the same equipment and procedures noted above.

Alternatively, the integrated transmittance can be associated with thecalculated percentage of the transparent substrate area that is notcovered by either the electrically-conductive silver metal electrodegrid in the touch region or by the electrically-conductive silverconnector wire pattern in the electrode connector regions.

In defining various dimensions of the silver main wires and silvermicro-wires provided in the electrically-conductive articles, eachdimension “average” is determined from at least 5 measurements of thespecific dimension using appropriate measurement techniques andequipment that would be known to one skilled in the art.

Unless otherwise indicated, the terms “electrode connector regions,”“BUS lines,” and “BUS regions” mean the same thing.

Uses

The conductive film element precursors can be used to formelectrically-conductive articles that also have various uses. Forexample, the electrically-conductive articles can be used as devicesthemselves or they can be used as components in devices having a varietyof applications including but not limited to, electronic, optical,sensory, and diagnostic uses. In particular, it is desired to use theconductive film element precursors to provide highlyelectrically-conductive silver metal electrode grids andelectrically-conductive silver metal connector wire patterns comprisingsilver metal lines having suitable height, width, and conductivity foruse in touch screen displays or as components of touch-screen devices.Such electronic and optical devices and components include but are notlimited to, radio frequency tags (RFID), sensors, touch-screen displays,and memory and back-panels for displays.

Conductive Film Element Precursors

The conductive film element precursors used in the practice of thisinvention comprise photosensitive silver halide(s) but they do notgenerally contain chemistry sufficient to provide color photographicimages. Thus, these “precursors” are considered to be black-and-whitephotosensitive materials forming metallic silver images followingexposure and processing, and are non-color image-forming.

The precursors and the resulting electrically-conductive articles,including the transparent substrate and all accompanying layers on oneor both supporting sides, are considered transparent in the touchregions in which the electrically-conductive silver metal electrodegrids are formed, and other transparent regions outside theelectrically-conductive silver metal electrode grids and theelectrically-conductive silver connector wire pattern, meaning that theintegrated transmittance over the visible region of the electromagneticspectrum (for example from 410 nm to 700 nm) through the entireelectrically-conductive article in these touch regions and othertransparent regions is 70% or more, or more likely at least 85%, or even90% or more. Integrated transmittance is measured as described above.

However, the electrode connector regions of the processed photosensitivesilver halide emulsion layers that are used to provide theelectrically-conductive silver connector wire patterns, are lesstransparent due to the higher coverage of silver metal formed in thoseelectrode connector regions. For example, such electrode connectorregions comprised of electrically-conductive silver connector wirepatterns generally have an integrated transmittance of less than 68%, orless than 50%, or even less than 40%.

The precursors can be formed by providing a non-color (that is, silvermetal image-forming black-and-white) photosensitive silver halideemulsion layer on one or both supporting sides (or planar sides asopposed to non-supporting edges) of a suitable transparent substrate ina suitable manner. Each photosensitive layer comprises a silver halide,or a mixture of silver halides, at a suitable silver coverage, such as atotal silver coverage of at least 2500 mg Ag/m², or at least 3500 mgAg/m² but usually less than 5000 mg Ag/m², for example up to andincluding 4950 mg Ag/m². However, higher amounts of silver coverage canbe used as would be known in the art. Thus, each photosensitive layerhas sufficient silver halide intrinsic or added spectral sensitizationto be photosensitive to preselected imaging irradiation (describedbelow). The photosensitive layers can be the same or different incomposition and spectral sensitization on the opposing supporting sidesof the transparent substrate.

The one or more silver halides are dispersed within one or more suitablehydrophilic binders or colloids as described below.

Such precursors are therefore treated (or processed) in such a manner asto convert the silver cations into silver metal particles (such as byreduction), and this treated precursor can then become anelectrically-conductive article of the present invention.

The precursors can have one essential layer on each supporting side ofthe transparent substrate, which essential layer is a photosensitivesilver halide emulsion layer. This essential layer can be disposed ononly one supporting side of the transparent substrate, but in manyduplex embodiments, it is disposed on both first supporting and opposingsecond supporting sides of the transparent substrate. Optional layers,such as hydrophilic overcoats and filter dye layers can also be presenton either or both supporting sides and are described below but they arenot essential to achieve the desired advantages of the presentinvention.

Transparent Substrates:

The choice of a transparent substrate generally depends upon theintended utility of the resulting electrically-conductive article suchthat the electrically-conductive article can be fabricated in a suitablemanner for a predetermined device. The transparent substrate can berigid or flexible, and generally has an integrated transmittance of atleast 90% and generally at least 95% over the visible region of theelectromagnetic spectrum (for example at least 410 nm and up to andincluding 700 nm). Integrated transmittance can be determined using aspectrophotometer and known procedures as described above.

Suitable transparent substrates include but are not limited to, glass,glass-reinforced epoxy laminates, cellulose triacetate, acrylic esters,polycarbonates, adhesive-coated polymer transparent substrates,polyester films, and transparent composite materials. Suitabletransparent polymers for use as transparent polymer substrates includebut are not limited to, polyethylene and other polyolefins, polyesterssuch as polyethylene terephthalate (PET), polyethylene naphthalate(PEN), poly-1,4-cyclohexanedimethylene terephthalate, poly(butyleneterephthalate), and copolymers thereof, polypropylenes, polyvinylacetates, polyurethanes, polyamides, polyimides, polysulfones,polycarbonates, and mixtures thereof. Other useful transparentsubstrates can be composed of cellulose derivatives such as a celluloseester, cellulose triacetate, cellulose diacetate, cellulose acetatepropionate, cellulose acetate butyrate, polyacrylates, polyether imides,and mixtures thereof.

Transparent polymeric substrates can also comprise two or more layers ofthe same or different polymeric composition so that the compositetransparent substrate (or laminate) has the same or different layerrefractive properties. The transparent substrate can be treated oneither or both supporting sides to improve adhesion of a photosensitivesilver halide emulsion or underlying layer. For example, the transparentsubstrate can be coated with a polymer adhesive layer, chemicallytreated, or subjected to a corona treatment on one or both supportingsides.

Commercially available oriented and non-oriented transparent polymerfilms, such as biaxially-oriented polypropylene or polyester, can beused. Such transparent substrates can contain pigments, air voids orfoam voids as long as desired integrated transmittance is obtained. Thetransparent substrate can also comprise microporous materials such aspolyethylene polymer-containing material sold by PPG Industries, Inc.,Pittsburgh, Pa. under the trade name of Teslin®, Tyvek® synthetic paper(DuPont Corp.). The transparent substrate also can be voided, whichmeans it contains voids formed as interstitial voids using added solidand liquid materials, or “voids” containing a gas. Some commercialmicrovoided products are commercially available as 350K18 fromExxonMobil and KTS-107 (from HSI, South Korea).

Biaxially-oriented sheets, while described as having at least one layer,can also be provided with additional layers that can serve to change theoptical or other properties of the biaxially oriented sheet. Such layersmight contain tints, antistatic or conductive materials, or slip agents.The biaxially-oriented extrusion can be carried out with as many as 10layers if desired, made with layers of the same polymeric material, orwith layers having different polymeric composition.

Flexible transparent substrates for the manufacture of flexibleelectronic devices or touch screen components facilitate rapidroll-to-roll manufacture. Estar® poly(ethylene terephthalate) films andcellulose triacetate films are particularly useful materials for makingflexible transparent substrates.

The transparent substrate used in the precursors can have a thickness ofat least 20 μm and up to and including 300 μm or typically at least 75μm and up to and including 200 μm. Antioxidants, brightening agents,antistatic or conductive agents, plasticizers, and other known additivescan be incorporated into the transparent substrate, if desired, inamounts that would be readily apparent to one skilled in the art as longas desired integrated transmittance is preserved.

Photosensitive Silver Halide Emulsion Layers:

The essential silver halide(s) in these layers comprise silver cationsof one or more silver halides that can be converted into silver metalparticles according to desired patterns upon imagewise exposure of eachphotosensitive silver halide emulsion layer. Such exposure is generallyachieved by imaging through a mask element that is designed withpredetermined patterns for both the electrically-conductive silver metalelectrode grid and the electrically-conductive silver connector wirepattern. The latent image(s) provided by this exposure can then bedeveloped into desired silver metal image(s) using known silverdevelopment procedures and chemistry (described below). The silverhalide (or combination of silver halides) is photosensitive, meaningthat radiation from UV to visible light (for example, of at least 200 nmand up to and including 750 nm radiation) is generally used to convertsilver cations to silver metal particles in a latent image. In someembodiments, the silver halide is present in combination with athermally-sensitive silver salt (such as silver behenate) and thephotosensitive silver halide emulsion layer can be both photosensitiveand thermally sensitive (that is, sensitive to thermal imaging energysuch as infrared radiation).

The useful photosensitive silver halides can be, for example, silverchloride, silver bromide, silver chlorobromoiodide, silverbromochloroiodide, silver chlorobromide, silver bromochloride, or silverbromoiodide that are prepared as individual compositions (or emulsions).The various halides are listed in the silver halide name in descendingorder of halide amount. In addition, individual silver halide emulsionscan be prepared and mixed to form a mixture of silver halide emulsionsthat are used on the same or different supporting sides of thetransparent substrate. In general, the useful silver halides comprise upto and including 100 mol % of chloride or up to and including 100 mol %of bromide, and up to and including 5 mol % iodide, all based on totalsilver. These silver halides are generally known as “high chloride” or“high bromide” silver halides and can be used to form “high chloride,”or “high bromide” emulsions, respectively.

The silver halide grains used in each photosensitive silver halideemulsion layer generally have an ESD of at least 30 nm and up to andincluding 300 nm, or more likely at least 50 nm and up to and including200 nm.

The coverage of total silver in each photosensitive silver halideemulsion layer is desirably at least 2500 mg Ag/m² and typically atleast 3500 mg Ag/m² and can be less than 5000 mg Ag/m², although higheramounts can be used.

The dry thickness of each photosensitive silver halide emulsion layer isgenerally at least 0.5 μm and up to and including 12 μm, andparticularly at least 0.5 μm and up to and including 7 μm.

The final dry photosensitive silver halide emulsion layer can be made upof one or more individually coated photosensitive silver halide emulsionsub-layers that can be applied using the same or different silver halideemulsion formulations. Each sub-layer can be composed of the same ordifferent silver halide(s), hydrophilic binders or colloids, andaddenda. The photosensitive silver halide emulsion sub-layers can havethe same or different amount of silver content.

The photosensitive silver halide(s) used in the photosensitive silverhalide emulsion layer on the first supporting side can be the same ordifferent from the photosensitive silver halide(s) used in the opposingsecond supporting side photosensitive silver halide emulsion layer.

The photosensitive silver halide grains (and any addenda associatedtherewith as described below) are dispersed (generally uniformly) in oneor more suitable hydrophilic binders or colloids to form a hydrophilicsilver halide emulsion. Examples of such hydrophilic binders or colloidsinclude but are not limited to, gelatin and gelatin derivatives,polyvinyl alcohol (PVA), poly(vinyl pyrrolidone) (PVP), casein, andmixtures thereof. Suitable hydrophilic colloids and vinyl polymers andcopolymers are also described in Section IX of Research Disclosure Item36544, September 1994 that is published by Kenneth Mason Publications,Emsworth, Hants, PO10 7DQ, UK. A particularly useful hydrophilic colloidis gelatin or a gelatin derivative of which several are known in theart.

The amount of hydrophilic binder or colloid in each photosensitivesilver halide emulsion layer can be adapted to the particular drythickness that is desired as well as the amount of silver halide that isincorporated. It can also be adapted to meet desired dispersibility,swelling, and layer adhesion to the transparent substrate. The amount ofhydrophilic binder or colloid is generally controlled to maximize theconductivity of the resulting silver metal particles in theelectrically-conductive articles.

In general, the one or more hydrophilic binders or colloids are presentin an amount of at least 10 weight % and up to and including 95 weight%, or more likely at least 10 weight % and up to and including 50 weight%, all based on the total solids in the dry photosensitive silver halideemulsion layer.

Some useful photosensitive silver halide emulsion layer compositionshave a relatively high silver ion/hydrophilic binder (for example,gelatin) weight (or volume) ratio. For example, a particularly usefulweight ratio of silver ions (and eventually silver metal) to hydrophilicbinder or colloid such as gelatin (or its derivative) is at least 0.1:1,or even at least 1.5:1 and up to and including 10:1. A particularlyuseful weight ratio of silver ions to the hydrophilic binder or colloidcan be at least 2:1 and up to and including 5:1. Other weight ratios canbe readily adapted for a particular use and dry layer thickness.Particularly useful silver ion/hydrophilic binder (gelatin) volume ratiois less than 0.5:1 or even less than 0.35:1.

The hydrophilic binder or colloid can be used in combination with one ormore hardeners designed to harden the particular hydrophilic binder suchas gelatin. Particularly useful hardeners for gelatin and gelatinderivatives include but are not limited to, non-polymeric vinyl-sulfonessuch as bis(vinyl-sulfonyl) methane (BVSM), bis(vinyl-sulfonyl methyl)ether (BVSME), and 1,2-bis(vinyl-sulfonyl acetamide)ethane (BVSAE).Mixtures of hardeners can be used if desired. The hardeners can beincorporated into each photosensitive silver halide emulsion layer inany suitable amount that would be readily apparent to one skilled in theart.

In general, each photosensitive silver halide emulsion layer can behardened so that it has a swell ratio of at least 150% but less than300% as determined by optical microscopy of element cross-sections, andthe swell ratio can be provided by use of appropriate amounts ofhardeners within the photosensitive silver halide emulsion layer, orhardeners within various processing solutions (described below).

If desired, the useful silver halides described above can be sensitizedto any suitable wavelength of exposing radiation. Organic sensitizingdyes can be used, but it can be advantageous to sensitize the silversalt to the UV portion of the electromagnetic spectrum without usingvisible light sensitizing dyes to avoid unwanted dye stains if theelectrically-conductive article containing the silver metal particles isintended to be transparent. Alternatively, the silver halides can beused without spectral sensitization beyond their intrinsic spectralsensitivities.

Non-limiting examples of addenda that can be included with the silverhalides, including chemical and spectral sensitizers, filter dyes,organic solvents, thickeners, dopants, emulsifiers, surfactants,stabilizers, hardeners, and antifoggants are described in ResearchDisclosure Item 36544, September 1994 and the many publicationsidentified therein. Such materials are well known in the art and itwould not be difficult for a skilled artisan to formulate or use suchcomponents for purposes described herein. Some useful silver saltemulsions are described, for example in U.S. Pat. No. 7,351,523(Grzeskowiak), U.S. Pat. No. 5,589,318, and U.S. Pat. No. 5,512,415(both to Dale et al.).

Useful silver halide emulsions containing silver halide grains that canbe reduced to silver metal particles can be prepared by any suitablemethod of grain growth, for example, by using a balanced double run ofsilver nitrate and salt solutions using a feedback system designed tomaintain the silver ion concentration in the growth reactor. Knowndopants can be introduced uniformly from start to finish ofprecipitation or can be structured into regions or bands within thesilver halide grains. Useful dopants include but are not limited to,osmium dopants, ruthenium dopants, iron dopants, rhodium dopants,iridium dopants, and cyanoruthenate dopants. A combination of osmium andiridium dopants such as a combination of osmium nitrosyl pentachlorideand iridium dopant is useful. Such complexes can be alternativelyutilized as grain surface modifiers in the manner described in U.S. Pat.No. 5,385,817 (Bell). Chemical sensitization can be carried out by anyof the known silver halide chemical sensitization methods, for exampleusing thiosulfate or another labile sulfur compound, alone or incombination with gold complexes.

Useful silver halide grains can be rounded cubic, octahedral, roundedoctahedral, polymorphic, tabular, or thin tabular emulsion grains. Suchsilver halide grains can be regular untwinned, regular twinned, orirregular twinned with cubic or octahedral faces. In one embodiment, thesilver halide grains can be rounded cubic having an ESD of less than 0.5μm and at least 0.05 μm.

Antifoggants and stabilizers can be added to give the silver halideemulsion the desired sensitivity, if appropriate. Useful antifoggantsinclude, for example, azaindenes such as tetraazaindenes, tetrazoles,benzotriazoles, imidazoles and benzimidazoles. Specific antifoggantsthat can be used include 6-methyl-1,3,3a,7-tetraazaindene,1-(3-acetamidophenyl)-5-mercaptotetrazole, 6-nitrobenzimidazole,2-methylbenzimidazole, and benzotriazole, individually or incombination.

The essential silver halide grains and hydrophilic binders or colloids,and optional addenda can be formulated and coated as a silver halideemulsion using suitable emulsion solvents including water andwater-miscible organic solvents. For example, useful solvents for makingthe silver halide emulsion or coating formulation can be water, analcohol such as methanol, a ketone such as acetone, an amide such asformamide, a sulfoxide such as dimethyl sulfoxide, an ester such asethyl acetate, liquid or low molecular weight poly(vinyl alcohol), or anether, or combinations of these solvents. The amount of one or moresolvents used to prepare the silver halide emulsions can be at least 30weight % and up to and including 50 weight % of the total formulationweight. Such coating formulations can be prepared using any of thephotographic emulsion making procedures that are known in the art.

Hydrophilic Overcoats

While the photosensitive silver halide emulsion layer, on either or bothsupporting sides of the transparent substrate, can be the outermostlayer in the precursor article, in many embodiments, there can be ahydrophilic overcoat disposed over each photosensitive silver halideemulsion layer. This hydrophilic overcoat can be the outermost layer inthe precursor (that is, there are no layers purposely placed over it oneither or both supporting sides of the transparent substrate). If bothsupporting sides of the transparent substrate comprise a photosensitivesilver halide layer, then a hydrophilic overcoat can be present on bothsupporting sides of the transparent substrate. Thus, a first hydrophilicovercoat is disposed over the first photosensitive silver halideemulsion layer, and a second hydrophilic overcoat is disposed over asecond photosensitive silver halide emulsion layer on the opposingsecond supporting side of the transparent substrate. In mostembodiments, each hydrophilic overcoat is directly disposed on eachphotosensitive silver halide emulsion layer, meaning that there are nointervening layers on the supporting sides of the transparent substrate.The chemical compositions and dry thickness of these hydrophilicovercoats can be the same or different, but in most embodiments theyhave essentially the same chemical composition and dry thickness on bothsupporting sides of the transparent substrate.

In some embodiments, each hydrophilic overcoat (first or second, orboth) comprises one or more silver halides in the same or differentamount so as to provide silver metal particles after exposure andprocessing, in an amount of at least 5 mg Ag/m² and up to and including150 mg Ag/m², or at least 5 mg Ag/m² and up to and including 75 mgAg/m². When present, the one or more silver halides in each hydrophilicovercoat can have a grain ESD of at least 100 nm and up to and including1000 nm, or at least 150 nm and up to and including 600 nm. In someembodiments, the one or more silver halides in each hydrophilic overcoathave a grain ESD that is larger than the grain ESD of the silver halidein the non-color hydrophilic photosensitive layer over which it isdisposed. In various embodiments, the silver halide(s) in eachhydrophilic overcoat comprises up to 100 mol % bromide or up to 100 mol% chloride, and up to and including 3 mol % iodide, all molar amountsbased on total silver content. In other embodiments, the silverhalide(s) in each hydrophilic overcoat comprises more chloride than thesilver halide in the non-color hydrophilic photosensitive layer overwhich it is disposed. This relationship can be the same or different onboth supporting sides of the transparent substrate in the “duplex”conductive film element precursors.

When present, the silver halide is dispersed (generally uniformly)within one or more hydrophilic binders or colloids in each hydrophilicovercoat, which hydrophilic binders or colloids include those describedabove for the non-color hydrophilic photosensitive layers. In manyembodiments, the same hydrophilic binders or colloids can be used in allof the layers of the precursor. However, different hydrophilic bindersor colloids can be used in the various layers, and on either or bothsupporting sides of the transparent substrate. The amount of one or morehydrophilic binders or colloids in each hydrophilic overcoat is the sameor different and generally at least 50 weight % and up to and including100 weight %, or typically at least 75 weight % and up to and including98 weight %, all based on total hydrophilic overcoat dry weight.

In some embodiments, the hydrophilic overcoat can further comprise oneor more radiation absorbers such as UV radiation absorbers in an amountof at least 5 mg/m² and up to and including 100 mg/m². Such UV radiationabsorbers can be “immobilized” meaning that they do not readily diffuseout of the hydrophilic overcoat.

The same hydrophilic binders or colloids are used if no silver halide ispresent, and in such embodiments, the hydrophilic binders or colloidscan comprise up to and including 100 weight % of the total hydrophilicovercoat dry weight.

Each hydrophilic overcoat can also comprise one or more hardeners for ahydrophilic binder or colloid (such as gelatin or a gelatin derivative).Useful hardeners are described above.

The dry thickness of the each hydrophilic overcoat can be at least 100nm and up to and including 800 nm or more particularly at least 300 nmand up to and including 500 nm. In embodiments containing silver halide,the grain ESD to dry thickness ratio in the hydrophilic overcoat can befrom 0.25:1 to and including 1.75:1 or more likely from 0.5:1 to andincluding 1.25:1.

Additional Layers:

In addition to the layers and components described above on one or bothsupporting sides of the transparent substrate, the precursors andelectrically-conductive articles can also include other layers that arenot essential but can provide additional properties or benefits,including but not limited to radiation absorbing filter layers, adhesionlayers, and other layers as are known in the black-and-whitephotographic art. The radiation absorbing filter layers can also beknown as “antihalation” layers that can be located between the essentiallayers and each supporting side of the transparent substrate. Forexample, each supporting side can have a radiation absorbing filterlayer disposed directly on it, and directly underneath thephotosensitive silver halide emulsion layer. Such radiation absorbingfilter layers can include one or more filter dyes that absorb in the UV,red, green, or blue regions of the electromagnetic spectrum, or anycombination thereof, and can be located between the transparentsubstrate and the photosensitive silver halide emulsion layer on each orboth supporting sides of the transparent substrate.

The duplex conductive film element precursors used in the presentinvention can comprise on the opposing second supporting side of thetransparent substrate, a second photosensitive silver halide emulsionlayer and optionally, a second hydrophilic overcoat disposed over thesecond photosensitive silver halide emulsion layer. A radiationabsorbing filter layer can be disposed between the opposing secondsupporting side of the transparent substrate and the secondphotosensitive silver halide emulsion layer, which radiation absorbingfilter layer can be the same as or different from the radiationabsorbing filter layer on the first supporting side of the transparentsubstrate. For example, such radiation absorbing filter layers caninclude one or more UV radiation absorbing compounds.

In many duplex conductive film element precursors, the secondphotosensitive silver halide emulsion layer and a second hydrophilicovercoat (if present) have the same composition as the firstphotosensitive silver halide emulsion layer and the first hydrophilicovercoat, respectively.

Preparing Conductive Film Element Precursors

The various layers are formulated using appropriate components andcoating solvents and are applied to one or both supporting sides of asuitable transparent substrate (as described above) using known coatingprocedures including those commonly used in the photographic industry(for example, bead coating, blade coating, curtain coating, spraycoating, and hopper coating). Each layer formulation can be applied toeach supporting side of the transparent substrate in single-passprocedures or in simultaneous multi-layer coating procedures. Knowndrying techniques can be used to dry each of the applied formulations.

Making Electrically-conductive Articles

The resulting conductive film element precursors can be used immediatelyfor an intended purpose, or they can be stored in roll or sheet form forlater use. For example, the precursors can be rolled up duringmanufacture and stored for use in a roll-to-roll imaging and processingprocess, and subsequently cut into desired sizes and shapes.

To imagewise expose a precursor, a suitable mask element or group ofmask elements are designed with predetermined patterns for bothelectrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns that areeventually formed in the electrically-conductive articles. As notedabove, the photosensitive silver halide emulsion layers in theprecursors are generally designed to accommodate both touch regionshaving desired electrically-conductive silver metal electrode grids, andelectrode connector regions that contain desired electrically-conductivesilver connector wire patterns to provide designed circuitry. Both touchregions and electrode connector regions are formed in the samephotosensitive silver halide emulsion layer on one or both supportingsides of the transparent substrate. The transparent regions outside ofthe electrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns generally containno silver metal particles.

Thus, one or both sides of a precursor are designed to be exposed tosuitable radiation to provide, in each photosensitive silver halideemulsion layer: (a) a latent electrically-conductive silver metalelectrode grid, and (b) a latent electrically-conductive silverconnector wire pattern that is different from the latentelectrically-conductive silver metal electrode grid. Each side of theprecursor can be imagewise exposed at the same time or they can beimagewise exposed at different times using different mask elements sothe opposing latent images in all regions are different in design, size,surface area covered by silver metal particles, or sheet resistivity.Opposing photosensitive silver halide emulsion layers can also bedesigned to have different wavelength sensitivity so that differentimaging (exposing) radiation wavelengths can be used for exposure ofopposing supporting sides.

Thus, photosensitive silver halides in photosensitive silver halideemulsion layers can be imagewise exposed to appropriate actinicradiation (UV to visible radiation) from a suitable source that is wellknown in the art such as a xenon lamp, mercury lamp, or other source ofradiation of from 200 nm and up to and including 700 nm.

The exposed precursors can be processed using various aqueous-basedprocessing solutions including at least solution physical developmentand silver halide fixing, to provide in each exposed photosensitivesilver halide emulsion layer: (a) a electrically-conductive silver metalelectrode grid from the latent electrically-conductive silver metalelectrode grid, (b) an electrically-conductive silver connector wirepattern from the latent electrically conductive silver connector wirepattern, and (c) transparent regions outside of both theelectrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern.

The resulting electrically-conductive silver metal electrode grid isformed in the touch region and generally has an integrated transmittanceof at least 75% (for example, the electrically-conductive silver metalelectrode grid covers 25% or less of the total touch region surfacearea). Moreover, the resulting electrically-conductive silver connectorwire pattern is formed in the electrode connector region and generallyhas an integrated transmittance of 68% or less (or 50% or less). Thus,the electrically-conductive silver connector wire pattern generallycovers more than 42% of the total electrode connector region. Integratedtransmittance is determined as described above. These amounts can be thesame or different on opposing supporting sides of the transparentsubstrate.

Prebath solutions can also be used to treat the exposed silver saltsprior to development. Such solutions can include one or more developmentinhibitors as described above for the developing solutions, and in thesame or different amounts. Effective inhibitors include but are notlimited to, benzotriazoles, heterocyclic thiones, andmercaptotetrazoles. The prebath temperature can be in a range asdescribed for development. Prebath time depends upon the concentrationand particular inhibitor, but it can range from at least 10 seconds andup to and including 4 minutes.

Processing the exposed silver halide in the latent images is generallyaccomplished firstly with one or more development steps during whichsilver ions in the silver halide latent images are reduced to silvermetal (or silver particles). Such development steps are generallycarried out using known aqueous developing solutions that are commonlyused in silver metal image-forming black-and-white photography andtypically include at least one solution physical development solution.

Numerous silver metal image-forming black-and-white developing solutions(identified also as “developers”) are known that can develop the exposed(latent image containing) silver halides described above to form silvermetal particles. One commercial silver metal image-formingblack-and-white silver halide developer that is useful is Accumax®silver halide developer. Silver metal image-forming black-and-whitedeveloping solutions are generally aqueous solutions including one ormore silver halide developing agents, of the same or different type,including but not limited to those described in Research Disclosure Item17643 (December, 1978) Item 18716 (November, 1979), and Item 308119(December, 1989) such as polyhydroxybenzenes (such as dihydroxybenzene,or in its form as hydroquinone, cathecol, pyrogallol,methylhydroquinone, and chlorohydroquinone), aminophenols such asp-methylaminophenol, p-aminophenol, and p-hydroxyphenylglycine,p-phenylenediamines, ascorbic acid and its derivatives, reductones,erythrobic acid and its derivatives, 3-pyrazolidones such as1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-3-pyrazolidone, and1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, pyrazolone,pyrimidine, dithionite, and hydroxylamines. These developing agents canbe used individually or in combinations thereof. One or more developingagents can be present in suitable amounts for example of at least 0.01mol/I and up to and including 1 mol/l.

The black-and-white developing solutions can also include auxiliarysilver developing agents that exhibit super-additive properties with adeveloping agent. Such auxiliary developing agents can include but arenot limited to, p-aminophenols and substituted or unsubstitutedphenidones, in suitable amounts such as at least 0.001 mol/l and up toand including 0.1 mol/l.

The concentration of the one or more auxiliary silver developing agentscan be less than the concentration of the one or more developing agentsas described above.

Useful silver metal image-forming black-and-white developing solutionscan also include one or more silver complexing agents (or silverligands) including but not limited to, sulfite, thiocyanate,thiosulfate, thiourea, thiosemicarbazide, tertiary phosphines,thioethers, amines, thiols, aminocarboxylates, triazolium thiolates,pyridines (including bipyridine), imidazoles, and aminophosphonates, insuitable amounts. For example, one or more alkali metal sulfites can bepresent in an amount of at least 0.1 mol/l and up to and including 1mol/l

The black-and-white developing solutions can also comprise one or morealkyl- or aryl-substituted or unsubstituted mercaptotetrazoles insuitable amounts for various purposes such as at least 0.25 mmol/l andup to and including 2.5 mmol/l. Useful mercaptotetrazoles include butare not limited to, alkyl-, aryl-, and heterocyclyl-substitutedmercaptotetrazoles. Examples of such compounds include but are notlimited to, 1-phenyl-5-mercaptotetrazole (PMT),1-ethyl-5-mercaptotetrazole, 1-t-butyl-5-mercaptotetrazole, and1-pyridinyl-5-mercaptotetrazoles.

Moreover, the black-and-white developing solution can also include oneor more development inhibitors in suitable amounts. Useful developmentinhibitors include but are not limited to, substituted and unsubstitutedbenzotriazole compounds such as 5-methylbenzotriazole, imidazoles,benzimidazole thiones, benzothiazole thiones, benzoxazole thiones, andthiazoline thiones, all in the same or different amounts as describedabove for the mercaptotetrazoles.

Other addenda that can be present in the black-and-white developingsolutions in known amounts include but are not limited to, metalchelating agents, preservatives (such as sulfites), antioxidants, smallamounts of water-miscible organic solvents (such as benzyl alcohol anddiethylene glycol), nucleators, as well as acids, bases (such as alkalihydroxides), and buffers (such as carbonate, borax, phosphates, andother basic salts) to establish a pH of at least 8 and generally of a pHof at least 9.5, or at least 11 and up to and including 14.

The silver halide developing solution can be supplied at workingstrength or in concentrated form that is diluted prior to or during useup to 5 times with water.

Multiple development steps can be used if desired. For example, a firstdeveloping solution can provide initial development to form silver metalnuclei and then a second developing solution can be used to provide“solution physical development” that improves conductivity of theresulting silver metal images.

A solution physical development step can be carried out using a solutionhaving a pH of at least 8 and up to and including 13. This silver halidesolution physical developing solution can comprise one or more primarydeveloping agents chosen from one or more of hydroquinone or itsderivatives or one or more ascorbic acid or derivatives thereof. Theprimary developing agents in the silver halide solution physicaldeveloping solution can be the same or different as the primarydeveloping agents in the silver halide developing solution describedabove.

The one or more primary developing agents in the silver halide solutionphysical developing solution can be present in a total amount of atleast 0.01 mol/l and up to and including 1 mol/l.

In addition, the silver halide solution physical developing solutioncomprises one or more silver halide dissolution catalysts as essentialcomponents in an amount of at least 0.001 mol/l and up to and including0.1 mol/l, or typically of at least 0.005 mol/l and up to and including0.05 mol/l.

Useful silver halide dissolution catalysts include but are not limitedto, alkali metal thiocyanate salts such as sodium thiocyanate andpotassium thiocyanate, thioethers such as 3,6-dithia-1,8-octanediol, andheterocyclic thiones such astetrahydro-4,6-dimethyl-1,3,5-triazine-2(1H)-thione, andtetrahydro-3-hydroxyethyl-1,3,5-triazine-2(1H)-thione. These compoundscan readily complex with silver.

In some embodiments, the silver halide solution physical developingsolution contains substantially no catalytic developing agents such asthose compounds described above for the silver halide developingsolution. The term “substantially no” means that less than 0.001 mol/lor even less than 0.0001 mol/l of such compounds are purposelyincorporated into or created in the solution.

The silver halide solution physical developing solution can furthercomprise one or more alkali metal sulfites include sodium sulfite,potassium sulfite, and mixtures thereof. The alkali metal sulfites canbe present in the silver halide solution physical developing solution ina total amount of at least 0.2 mol/l and up to and including 3 mol/lwhen potassium sulfite or sodium sulfite is used or particularly whenonly potassium sulfite is used.

The silver halide solution physical developing solution can furtherinclude one or more polyaminopolycarboxylic acid salts that are capableof complexing with silver ion, including but not limited to,diethylenetriamine pentaacetic acid, pentasodium salt and other similarcompounds known in the art. Such compounds can be useful particularlywhen a sulfite is not present. Such compounds can be present in anamount of at least 0.001 mol/l and up to and including 0.03 mol/l.

The silver halide solution physical developing solution can also includeone or more metal ion complexing agents that can complex with silver,calcium, iron, magnesium, or other metal ions that can be present.Silver or calcium metal ion complexing agents can be particularly usefulin a total amount of at least 0.001 mol/l.

Particularly useful silver halide solution physical developing solutionsinclude but are not limited to, hydroquinone or a derivative thereof andsodium thiocyanate or potassium thiocyanate, and optionally a sulfiteand calcium or silver metal ion complexing agent.

The silver halide physical solution developing solution can be providedat working strength or in a concentrated form that is suitably dilutedprior to or during processing using known processing equipment andprocedures. For example, the silver halide physical developing solutioncan be concentrated at least 4 times compared to a desired workingstrength concentration.

Useful development temperatures can range from at least 15° C. and up toand including 60° C. Useful development times can range from at least 10seconds and up to and including 10 minutes but more likely up to andincluding 1 minute. The same time or temperature can be used forindividual development steps and can be adapted to develop at least 90mol % of the exposed silver halide in all latent silver halide images.If a prebath solution is not used, the development time can be extendedappropriately. Any exposed silver halide(s) in a hydrophilic overcoat isalso developed during the development step(s). Washing or rinsing can becarried out with water after or between any development steps.

After development of the exposed silver halide to silver metal, theundeveloped silver halide in all photosensitive silver halide emulsionlayers is generally removed by treating the developed silver-containingarticle with a silver halide fixing solution. Silver halide fixingsolutions are well known in the black-and-white photographic art andcontain one or more compounds that complex the silver ion for removalfrom the layers. Thiosulfate salts are commonly used in silver halidefixing solutions. The silver halide fixing solution can optionallycontain a hardening agent such as alum or chrome-alum. The developedfilm can be processed in a silver halide fixing solution immediatelyafter development, or there can be an intervening stop bath or waterwash or rinse, or both stop bath and water rinse. Fixing can be carriedout at any suitable temperature and time such as at least 20° C. for atleast 30 seconds.

Fixing then leaves the silver metal particles in theelectrically-conductive silver metal electrode grid andelectrically-conductive silver connector wire pattern in each formerlyphotosensitive silver halide emulsion layer. Fixing also removes anynon-developed silver halide in any hydrophilic overcoat.

After fixing, the resulting intermediate article can be washed or rinsedin water that can optionally include surfactants or other materials toreduce water spot formation upon drying.

In addition, after fixing and washing, the intermediate article can befurther treated to further enhance the conductivity of the silver metalon each supporting side of the transparent substrate. A variety of wayshave been proposed to carry out this “conductivity enhancement” process.For example, U.S. Pat. No. 7,985,527 (Tokunaga) and U.S. Pat. No.8,012,676 (Yoshiki et al.) describe conductivity enhancement treatmentsusing hot water baths, water vapor, reducing agents, or halides.

It is also possible to enhance conductivity of the silver metalparticles by repeated contact with a conductivity enhancing agent,washing, drying, and repeating this cycle of treating, washing, anddrying one or more times. Useful conductivity enhancing agents includebut are not limited to, sulfites, borane compounds, hydroquinones,p-phenylenediamines, and phosphites. The treatment can be carried out ata temperature of at least 30° C. and up to and including 90° C. for atleast 0.25 minute and up to and including 30 minutes.

It can be useful in some embodiments to treat theelectrically-conductive article with a hardening bath after fixing andbefore drying to improve the physical durability of the resultingelectrically-conductive article. Such hardening baths can include one ormore known hardening agents in appropriate amounts that would be readilyapparent to one skilled in the art. It can be desired to control theswelling of the conductive film element precursor at one or more stagesof processing, so that swelling is limited to a desired amount of theoriginal precursor dry thickness.

Additional treatments such as a stabilizing treatment can also becarried out before a final drying if desired, at any suitable time andtemperature.

Drying at any stage can be accomplished in ambient conditions or byheating, for example, in a convection oven at a temperature above 50° C.but below the glass transition temperature of the transparent substrate.

While imagewise exposing and processing of each side of the precursorcan be carried out at different times or sequences, in many embodiments,imagewise exposing and processing of the photosensitive silver halideemulsion layer on the opposing second supporting side is carried outsimultaneously with imagewise exposing and processing of thephotosensitive silver halide emulsion layer on the first supportingside.

The result of the processing steps is a electrically-conductive articleof the present invention of any of the embodiments described above.

Electrically-Conductive Silver Metal Electrode Grids:

The electrically-conductive silver metal electrode grid on the firstsupporting side and the optional electrically-conductive silver metalgrid on the opposing second supporting side can be the same or differentin composition, pattern arrangement, conductive line thickness, or shapeof the grid lines (for example, a pattern of polygons including but notlimited to, a pattern of rectangles, triangles, hexagons, rhombohedrals,octagons, or squares), circles or other curved lines, or randomstructures, all corresponding to the predetermined pattern in the maskelement used during imagewise exposure. For example, in one embodiment,the electrically-conductive silver metal electrode grid on the firstsupporting side can be arranged in a square pattern, and theelectrically-conductive silver metal electrode grid on the opposingsupporting second side can be arranged in a diamond pattern. In eachinstance, the silver grid lines in the electrically-conductive silvermetal grids form a net-like structure. In other embodiments, the variouspatterns on opposing supporting sides can be arranged in an alternativearrangement so that the electrically-conductive silver metal electrodegrid on one supporting only partially covers the electrically-conductivesilver metal electrode grid on the opposing supporting side, somewhat asis shown in FIG. 14 of U.S. Patent Application Publication 2011/0289771(noted above).

The electrically-conductive silver wires in the electrically-conductivesilver metal electrode grid can have any desired length that is usuallyat least 1 cm and up to and including 10 meters, and they can have anaverage dry thickness (line width, one outer edge to the other outeredge) and dry height that are the same or different, and are generallyless than 50 μm, but more likely at least 1 μm and up to and including20 μm, or particularly at least 5 μm and less than 15 μm or even 10 μmor less.

Electrically-Conductive Silver Connector Wire Patterns:

Each electrically-conductive silver connector wire pattern comprises atleast one and more likely at least two adjacent (for example, at leastfirst and second) silver main wires, and there can be up to 1000 or evenmore of these silver main wires in each electrically-conductive silverconnector wire pattern. The number of silver main wires can be differenton opposing supporting sides of the transparent substrate. Each silvermain wire comprises two or more (and up to 10 or even more) silvermicro-wires that are electrically connected to a silver end wire at anend of the at least one (or generally two adjacent) silver main wires.Thus, the two or more silver micro-wires and the silver end wire in eachsilver main wire form a bundled pattern. Many bundled patterns comprisea plurality of silver main wires, each of which comprises a plurality ofsilver micro-wires and all of the silver micro-wires are electricallyconnected at both ends to suitable silver end wires. As described below,such bundled patterns can also include one or more silver cross-wires.

In some embodiments, each silver main wire can comprise from two toeight silver micro-wires that, with the suitable silver end wires, forma bundled pattern. Thus, each bundled pattern in such embodimentscomprises a silver end wire at each end of the at least two adjacentsilver main wires (and thus at the end of each pair of adjacent silvermain wires in the bundled pattern) that electrically connects with thetwo to eight silver micro-wires in each bundled pattern.

The average distance between any two adjacent silver main wires isgreater than the average distance between any two adjacent silvermicro-wires in each bundled pattern. For example, the average distancebetween any two adjacent silver main wires can be greater than theaverage distance between any two adjacent silver micro-wires in eachbundled pattern by at least 30%, or more typically at least 100%. Forexample, the average distance between two adjacent silver main wires canbe at least 5 μm, or at least 10 μm, or even at least 20 μm. Such“average distances” are measured from the outer edge of a given silvermicro-wire to the nearest outer edge of an adjacent silver micro-wire,of from the outer edge of the outermost silver micro-wire in a givensilver main wire to the outer edge of the closest outermost silvermicro-wire in an adjacent silver main wire.

Within each silver main wire, the average total length of each silvermicro-wire can be at least 1 mm or typically at least 5 mm and up to andincluding 1000 mm.

The average distance between any two adjacent silver micro-wires in eachbundled pattern (of each and any silver main wire) can be at least 2 μmand up to and including 10 μm (wherein “average distance” is definedabove). In particular, the average distance between any two adjacentsilver micro-wires in each bundled pattern (or each and any silver mainwire) can be at least 5 μm and up to and including 8 μm.

The ratio of the average width (outer edge to opposing outer edge) ofeach silver micro-wire to the average distance between two adjacentsilver micro-wires in each bundled pattern (or each and any silver mainwire) can be at least 0.5:1 but less than 2:1, or typically at least 1:1and up to and including 2:1.

It is also desirable that for each silver micro-wire, the ratio ofmaximum height to minimum height can be at least 1.05:1, or typically atleast 1.1:1. In some embodiments of at least one of the silvermicro-wires (and in most embodiments, each silver micro-wire), themaximum height of the silver micro-wire can be equivalent (varying byless than 10%) to the center height of the silver micro-wire wherein the“center” is determined to be essentially equidistant between the twoouter edges of the silver micro-wire. “Essentially equidistant” meansthat the distances between the two outer edges vary by no more than 10%.

In other embodiments of at least one of the silver micro-wires (and inmost embodiments, each silver micro-wire), the maximum height can becloser to a micro-wire outer edge than to micro-wire center height (atleast 51% closer to the outer edge than to the center). For example, themaximum height can actually be located at one or both outer edges ofsome silver micro-wires.

It is also possible that for each silver micro-wire, the ratio ofmaximum height to average height can be at least 1.01:1, or moretypically at least 1.01:1 to and including 1.05:1.

The average width of each silver micro-wire (from one outer edge to theother outer edge) in each bundled pattern can be at least 2 μm and up toand including 20 μm, or typically up to and including 15 μm or typicallyfrom 2 μm and up to and including 12 μm.

Moreover, each bundled pattern can comprise at least one silvercross-wire between adjacent silver micro-wires that is not at the end ofthe adjacent silver micro-wires. Typically, adjacent silver micro-wirescomprise multiple silver cross-wires that are not at the end of theadjacent silver micro-wires. A skilled worker can design each bundledpattern to have as many silver cross-wires as can be desired for a givenelectrically-conductive silver connector wire pattern.

The silver cross-wires can be arranged in any suitable frequency ordirectional arrangement and such arrangement can be the same ordifferent for each set of adjacent silver micro-wires.

For example, each bundled pattern can comprise multiple (two or more)silver cross-wires between adjacent silver micro-wires, wherein themultiple silver cross-wires are arranged at a distance from each otherof at least 100 p.m.

Moreover, each bundled pattern can comprise multiple (two or more)silver cross-wires in a set of adjacent silver micro-wires that areoffset from multiple silver cross-wires in an another set of adjacentsilver micro-wires (for example alternating along the adjacent sets ofadjacent silver micro-wires). All of the silver cross-wires cantherefore be arranged in the same or different manner among all of theadjacent sets of adjacent silver micro-wires.

In some embodiments, each of the multiple silver cross-wires issubstantially perpendicular (intersection at an angle of substantially90°) to the adjacent silver micro-wires. In other embodiments, each ofthe multiple silver cross-wires intersects the adjacent silvermicro-wires at an angle that is greater than or less than 90°. The twoor more silver micro-wires can be substantially parallel (for example,the adjacent silver micro-wires are substantially parallel).

The present invention can also be exemplified in reference to FIGS. 1-11that are now explained.

In FIG. 1, electrically-conductive article 5 has transparent substrate40 on which electrically-conductive silver connector wire pattern 8 isdisposed, which electrically-conductive silver connector wire pattern 8comprises multiple silver main wires 10. Each silver main wire 10comprises multiple adjacent silver micro-wires 20 (four shown in FIG. 1for each silver main wire 10). Silver end wire 22 is shown at the end ofeach silver main wire 10. Outside of electrically-conductive silverconnector wire pattern 8 is transparent region 50 (referenced in somebut not all places). Transparent regions (not shown with additionalreference numbers) are also present between (or outside) adjacent silvermain wires 10 and between (or outside) adjacent silver micro-wires 20 ineach silver main wire 10. All transparent regions contain no significantsilver halide or silver metal. In electrically-conductive article 5,adjacent silver main wires (at least one identified as 10) are separatedby distance S1 and the distance between adjacent silver micro-wires (oneidentified as 20) is shown by S2. As described above, the average S1 isgreater than the average S2 in each bundled pattern (silver main wire10). Representative average silver micro-wire 20 width is shown as W andaverage silver micro-wire length is shown as L. Each silver micro-wire20 can have essentially the same or different L and W dimensions. Inmost embodiments, such dimensions are the same for each silvermicro-wire in a given silver main wire.

FIG. 2 shows a schematic cross-section of electrically-conductivearticle 5 comprising transparent substrate 40 having first supportingside 42 and opposing second supporting side 44. A representative silvermicro-wire 20 is shown on both first supporting side 42 and opposingsecond supporting side 44.

In the cross-section view shown in FIG. 3A, a portion of photosensitivesilver halide emulsion layer 15 is disposed on a supporting side (eitherfirst supporting side or opposing second supporting side) of transparentsubstrate 40 having first supporting side 42 and opposing secondsupporting side 44. This portion of photosensitive silver halideemulsion layer 15 contains multiple non-exposed and non-developed silverhalide grains 60 surrounded by hydrophilic binder 64.

FIG. 3B shows a similar view as FIG. 3A but silver micro-wire 20 isdisposed on transparent substrate 40 having first supporting side 42 andopposing second supporting side 44, which silver micro-wire 20 containsmultiple silver metal particles 62 that can be derived from exposure andsilver halide development of the multiple silver halide grains 60surrounded by hydrophilic binder 64, shown in the portion ofphotosensitive silver halide emulsion layer 15 illustrated in FIG. 3A.

FIG. 4 is similar to FIG. 1 and shows electrically-conductive article 5comprising transparent substrate 40 on which electrically-conductivesilver connector wire pattern 8 is disposed. Electrically-conductivesilver connector wire pattern 8 comprises multiple silver main wires 10.Only three silver main wires 10 are shown but electrically-conductivesilver connector wire pattern 8 can have as few as two silver mainwires. Moreover, while only four silver micro-wires 20 are shown foreach silver main wire 10, the number of silver micro-wires in each mainwire can be as few as two and up to and including ten. Silver end wires22 are shown at the end of each set of adjacent silver micro-wires 20and various silver cross-wires 24 (only some are referenced) are shownat the same interval along silver micro-wires 20. Outside ofelectrically-conductive silver connector wire pattern 8 is transparentregion 50 (referenced in only some places), but transparent regions (notreferenced) also exist between adjacent silver micro-wires and betweenadjacent silver main wires.

FIG. 5 is similar to FIG. 4 but silver cross-wires 24 are arranged atdifferent intervals along silver micro-wires 20 and are offset betweenpairs of adjacent silver micro-wires 20. Thus, each bundled pattern orsilver main wire 10 comprises multiple silver cross-wires 24 in a set ofadjacent silver micro-wires 20, which are offset from multiple silvercross-wires 24 in an adjacent set of adjacent silver micro-wires 20.

FIG. 6 shows representative portions of some embodiments of the methodused to make the electrically-conductive articles in which a conductivefilm element precursor (“precursor”) is provided in feature 100,imagewise exposed to suitable radiation in feature 105, and theresulting latent silver is processed [including development usingsuitable silver metal image-forming black-and-white developingsolution(s)] in the precursor in feature 110.

FIG. 7 shows representative portions of other embodiments in which aprovided duplex conductive film element precursor (“precursor”) isimagewise exposed in feature 105 in two individual features of imagewiseexposure of a first side of the duplex conductive film element precursorin feature 107 and sequential imagewise exposure of the second (oropposing) side of the duplex conductive film element precursor infeature 109, followed by processing (including development) of theresulting latent silver in both imagewise exposed sides of the precursorin feature 110.

FIG. 8 shows representative portions of yet another variation in whichimagewise exposure feature 105 is carried out simultaneously for bothfirst and second sides of a duplex conductive film element precursor(“precursor”) as shown in features 107 and 109, and then followed byprocessing (including development) of latent silver on both sides of theimagewise exposed precursor in feature 110.

Still other representative portions of the method of this invention areshown in FIG. 9 in which imagewise exposure of a first side of a duplexconductive film element precursor (“precursor”) is provided in 107,which imagewise exposed first side is then processed (for example,development) to provide silver metal particles from latent silver infeature 112. The second (or opposing) side of the duplex conductive filmelement precursor is then imagewise exposed in 109 following byappropriate processing (including development) of latent silver tosilver metal particles in the precursor in feature 114.

FIG. 10 is a schematic cross-sectional view of a typical silvermicro-wire 20 that has a rounded upper and outer surface, and isdisposed on transparent substrate 40 having first supporting side 42 andopposing second supporting side 44. Silver micro-wire 20 is thereforecomposed of multiple silver metal particles 62 surrounded by hydrophilicbinder 64, which have been derived for example from appropriate silverhalide grains using the chemical compositions, appropriate exposure, andprocessing chemistry described above. As shown in FIG. 10, silvermicro-wire 20 has average width W, silver micro-wire maximum height D1,and silver micro-wire minimum height D2, wherein silver micro-wiremaximum height D1 is greater than silver micro-wire minimum height D2for example by a ratio of at least 1.05:1. While FIG. 10 illustrates asilver micro-wire that has uniform dimensions and contours, it would beunderstood by a skilled artisan that the drawn illustration isrepresentative only and that actual silver micro-wires produced in thepractice of this invention can have more irregular outer surfaces andshapes.

FIG. 11 is another schematic cross-sectional view showing a differentshape for silver micro-wire 20 containing multiple silver metalparticles 62 surrounded in hydrophilic binder 64, which silvermicro-wire 20 is disposed on transparent substrate 40 having firstsupporting side 42 and opposing second supporting side 44. Silvermicro-wire minimum height D2 is at or near the center of silvermicro-wire 20, and silver micro-wire minimum height D2 is less thansilver micro-wire maximum height D1 that is near or at either or bothouter edges of silver micro-wire 20. As one skilled in the art wouldunderstand, such illustration of silver micro-wire 20 is representativeonly and actual silver micro-wires produced in the practice of thisinvention can exhibit maximum and minimum heights that vary considerablyfrom that shown and can thus have more irregular outer surfaces.

The present invention provides at least the following embodiments andcombinations thereof, but other combinations of features are consideredto be within the present invention as a skilled artisan would appreciatefrom the teaching of this disclosure:

1. An electrically-conductive article comprising a transparent substratehaving a first supporting side and an opposing second supporting side,the first supporting side comprising: (a) a electrically-conductivesilver metal electrode grid, (b) an electrically-conductive silverconnector wire pattern, and optionally, (c) transparent regions outsideof both the electrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern,

wherein:

(i) the electrically-conductive silver connector wire pattern comprisesat least one silver main wire that comprises two or more silvermicro-wires that are electrically connected to a silver end wire at anend of the at least silver main wire, the two or more silver micro-wiresand the silver end wire in the at least one silver main wire forming abundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1;

(iv) the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 68%; and

(v) for each silver micro-wire, the ratio of maximum height to minimumheight is at least 1.05:1.

2. The electrically-conductive article of embodiment 1, wherein theelectrically-conductive silver connector wire pattern comprises at leasttwo adjacent silver main wires, and the average distance between the atleast two adjacent silver main wires is greater than the averagedistance between any two adjacent silver micro-wires in each bundledpattern.

3. The electrically-conductive article of embodiment 2, wherein theaverage distance between any two adjacent silver micro-wires in eachbundled pattern is at least 2 μm and up to and including 10 μm.

4. The electrically-conductive article of any of embodiments 1 to 3,further comprising on the opposing second supporting side of thetransparent substrate: (a) an opposing electrically-conductive silvermetal electrode grid, (b) an opposing electrically-conductive silverconnector wire pattern, and optionally, (c) transparent regions outsideof both the opposing electrically-conductive silver metal electrode gridand the opposing electrically-conductive silver connector wire pattern,

wherein, on the opposing second supporting side of the transparentsubstrate:

(i) the opposing electrically-conductive silver connector wire patterncomprises at least one silver main wire that comprises two or moresilver micro-wires that are electrically connected to a silver end wireat an end of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1;

(iv) the opposing electrically-conductive silver connector wire patternhas an integrated transmittance of less than 68%; and

(v) for each silver micro-wire, the ratio of maximum height to minimumheight is at least 1.05:1.

5. The electrically-conductive article of embodiment 4, wherein theopposing electrically-conductive silver connector wire pattern comprisesat least two adjacent silver main wires, and the average distancebetween these at least two adjacent silver main wires is greater thanthe average distance between any two adjacent silver micro-wires in eachbundled pattern.

6. The electrically-conductive article of embodiment 5, wherein theaverage distance between the at least two adjacent silver main wires isgreater than the average distance between any two adjacent silvermicro-wires in each bundled pattern.

7. The electrically-conductive article of any of embodiments 4 to 6,wherein the average distance between any two adjacent silver micro-wiresin each bundled pattern on the opposing second supporting side of thetransparent substrate is at least 2 μm and up to and including 10 μm.

8. The electrically-conductive article of any of embodiments 3 to 7,wherein the electrically-conductive silver metal electrode grid on thefirst supporting side is different from the electrically-conductivesilver metal electrode grid on the opposing second supporting side ofthe transparent substrate, in one or more of grid pattern, surface areacovered by the silver metal grid, or sheet resistivity.

9. The electrically-conductive article of any of embodiments 1 to 8,wherein for each silver micro-wire, the ratio of maximum height tominimum height is at least 1.1:1.

10. The electrically-conductive article of any of embodiments 1 to 9,wherein for at least one silver micro-wire, its maximum height is itscenter height.

11. The electrically-conductive article of any of embodiments 1 to 9,wherein for at least one silver micro-wire, the location of the maximumheight is closer to the outer edge than to the center of thesilver-micro-wire.

12. The electrically-conductive article of any of embodiments 1 to 11,wherein the average width of each silver micro-wire is at least 0.5 μmand up to and including 10 μm.

13. The electrically-conductive article of any of embodiments 1 to 12,wherein each bundled pattern comprises at least one silver cross-wirebetween adjacent silver micro-wires that is not at the end of theadjacent silver micro-wires.

14. The electrically-conductive article of any of embodiments 1 to 13,wherein each bundled pattern comprises multiple silver cross-wiresbetween adjacent silver micro-wires, wherein the multiple silvercross-wires are arranged at a distance from each other of at least 100μm.

15. The electrically-conductive article of any of embodiments 1 to 14,wherein each bundled pattern comprises multiple silver cross-wires in aset of adjacent silver micro-wires that are offset from multiple silvercross-wires in another set of adjacent silver micro-wires.

16. The electrically-conductive article of any of embodiments 1 to 15,wherein each of the multiple silver cross-wires is substantiallyperpendicular to the adjacent silver micro-wires.

17. The electrically-conductive article of any of embodiments 1 to 16,wherein each of the at least two adjacent silver main wires comprisesfrom two to ten silver micro-wires in a bundled pattern.

18. The electrically-conductive article of any of embodiments 1 to 17,wherein the average distance between the at least two adjacent silvermain wires is greater than the average distance between any two adjacentsilver micro-wires in each bundled pattern by at least 30%.

19. The electrically-conductive article of any of embodiments 1 to 18,wherein the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 1:1 and up to and including 2:1.

20. The electrically-conductive article of any of embodiments 1 to 19,wherein the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 50% and theelectrically-conductive silver metal electrode grid has an integratedtransmittance of at least 90%.

21. A touch screen device comprising the electrically-conductive articleof any of embodiments 1 to 20.

22. A method for providing a electrically-conductive article of any ofembodiments 1 to 20, the method comprising:

imagewise exposing a conductive film element precursor that comprises atransparent substrate comprising a first supporting side and an opposingsecond supporting side and a photosensitive silver halide emulsion layeron at least the first supporting side, to radiation to provide, in thephotosensitive silver halide emulsion layer on at least the firstsupporting side: (a) a latent electrically-conductive silver metalelectrode grid, (b) an latent electrically-conductive silver connectorwire pattern different from the latent electrically-conductive silvermetal electrode grid, and optionally, (c) transparent regions outside ofboth the latent electrically-conductive silver metal electrode grid andthe latent electrically-conductive connector wire pattern; and

processing the latent electrically-conductive silver metal electrodegrid and the latent electrically-conductive silver connector wirepattern using at least solution physical development and silver halidefixing, to provide: (a) a electrically-conductive silver metal electrodegrid from the latent electrically-conductive silver metal electrodegrid, (b) an electrically-conductive silver connector wire pattern fromthe latent electrically-conductive silver connector wire pattern, andoptionally, (c) transparent regions outside of both theelectrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern according to anyof embodiments 1 to 20.

The present invention can be carried out using a photosensitive silverhalide emulsion layer (from the silver halide emulsion described below)that can be disposed on one or both supporting sides of a transparentpoly(ethylene terephthalate) film substrate in any suitable coatingmanner to form a conductive film element precursor used in the presentinvention.

The conductive film element precursors can also be prepared using a 100μm poly(ethylene terephthalate) substrate on which any suitablenon-color photosensitive silver halide emulsion can be hardened usingBVSM [1,1′-(methylene(sulfonyl))bis-ethane] and disposed at 0.5 weight %of total gelatin. However, underneath the silver halide emulsion layer,a filter layer can be directly disposed on the transparent substrate forUV absorption, containing 1500 mg/m² of gelatin and 300 mg/m² ofTINUVIN® 328 UV absorbing dye (for example, from BASF).

The non-color photosensitive silver halide emulsion layer can beprovided with a silver (Ag) to gelatin weight ratio of 2.33:1 (or at avolume ratio of about 0.233:1). If desired, an outermost hydrophilicovercoat layer can be provided over the non-color photosensitive silverhalide emulsion layer, containing 488 mg/m² of gelatin, 6 mg/m² of 0.6μm insoluble polymeric matte particles, and conventional coatingsurfactants.

This conductive film element precursor can be imagewise exposed on oneor both sides using a suitable exposing device through the same ordifferent mask elements that have predetermined reverse images for theeventual desired electrically-conductive silver wire electrode grid andan electrically-conductive silver connector wire pattern on one or bothsupporting sides of the precursor. Upon exposure of one or bothphotosensitive silver halide emulsion layers, (a) a latentelectrically-conductive silver wire electrode grid, (b) a latentelectrically-conductive silver connector wire pattern different from thelatent electrically-conductive silver wire electrode grid, andoptionally, (c) transparent regions outside of both the latentelectrically-conductive silver halide electrode grid and the latentelectrically-conductive silver connector wire pattern can be formed.

Following imagewise exposure, each latent electrically-conductive silvermetal electrode grid and latent electrically-conductive silver connectorwire pattern can be processed using at least solution physicaldevelopment and silver halide fixing, to provide: (a) aelectrically-conductive silver metal electrode grid from the latentelectrically-conductive silver metal electrode grid, (b) anelectrically-conductive silver connector wire pattern from the latentelectrically-conductive silver connector wire pattern, and (c)transparent regions outside of both the electrically-conductive silvermetal electrode grid and the electrically-conductive silver connectorwire pattern, in a resulting electrically-conductive article.

Such processing can be carried out using the processing solutionsdescribed below, so that the resulting electrically-conductive articlecan have one or more of the properties (i) through (v) described above.

TABLE I Processing Sequence Processing Processing ProcessingStep/Solution Temperature (° C.) Time, (minutes) Developing/developer 140 0.5 Washing/rinsing with water 40 1.0 Developing/developer 2 40 3.0Fixing/fixing solution 40 1.77 Washing/rinsing with water 40 1.0Conductivity 60 2.0 Enhancement/Conductivity Enhancement SolutionWashing/rinsing with water 40 1.0 Drying 60 15.0 Conductivity 60 2.0Enhancement/Conductivity Enhancement Solution Washing/rinsing with water40 1.0 Drying 60 15.0 Conductivity 60 2.0 Enhancement/ConductivityEnhancement Solution Washing/rinsing with water 40 1.0 Drying 60 15.0Stabilizing/Stabilizer Solution 40 1.0 Washing/rinsing with water 40 1.0

The aqueous processing solutions that can be used in the notedprocessing steps are described below in TABLES II through VI, all ofwhich can be prepared in de-mineralized water. Drying can be carried outusing a convection oven.

TABLE II Developer 1 Component Amount (g/liter) Potassium Hydroxide(45.5 wt. %) 10.83 Sodium Bromide 5.00 4,4-Dimethyl-1-phenyl-3- 0.33pyrazolidinone 1-Phenyl-5-mercaptotetrazole 0.13 5-methylbenzotriazole*0.17 Sodium hydroxide (50 wt. %) 1.82 Phosphonic acid, 0.29[nitrilotris(methylene)]tris-, pentasodium saltN,N′-1,2-ethanediylbis(N- 1.77 (carboxymethyl)glycine, Sodium carbonatemonohydrate 8.33 Potassium Sulfite (45 wt. %) 83.33 Hydroquinone 12.505,5′-[Dithiobis(4,1- 0.12 phenyleneimino)]bis(5-oxo- pentanoic acid

TABLE III Developer 2 Component Amount (g/liter) Sodium Sulfite 92.54Hydroquinone 4.63 N,N-bis(2-(bis(carboxymethyl)- 0.950 amino)ethyl)-glycine, pentasodium salt Sodium tetraborate pentahydrate 2.830 Sodiumthiocyanate 0.42

TABLE IV Fixing Solution Component Amount (g/liter) Acetic Acid 24.43Sodium hydroxide (50 wt. %) 10.25 Ammonium thiosulfite 246.50 Sodiummetabisulfite 15.88 Sodium tetraborate pentahydrate 11.18 Aluminumsulfate (18.5 wt. %) 36.26

TABLE V Conductivity Enhancement Solution Component Amount (g/liter)[1,2-Bis(3-aminopropylamino)- 11.15 ethane] Triethanolamine (99 wt. %)38.6 Triethanolamine hydrochloride 14.0 Dimethylaminoborane 12.0 Sodiumlauryl sulfate 0.030 2,2-Bipyridine 1.00

TABLE VI Stabilizer Solution Component Amount (g/liter) Sodium hydroxide(50 wt. %) 0.29 N-[3-(2,5-dihydro-5-thioxo-1H- 0.82tetrazol-1-yl)phenyl]acetamide

Other electrically-conductive articles can be similarly prepared from aconductive film element precursor that differs from those describedabove only in the composition of the hydrophilic overcoat layer that canbe as follows:

488 mg/m² of gelatin, 6 mg/m² of 0.6 μm insoluble polymeric matteparticles, 20 mg/m² of a silver halide emulsion having a composition of98 mol % silver chloride and 2 mol % silver iodide (emulsion grainshaving rounded cubic morphology and an edge length 0.36 μm), 25 mg/m² ofTINUVIN® 328 UV radiation absorber, and conventional surfactants.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

PARTS LIST

-   5 Electrically-conductive article-   8 Electrically-conductive silver connector wire pattern-   10 Silver main wire-   15 Portion of photosensitive silver halide emulsion layer-   20 Silver micro-wire-   22 Silver end wire-   24 Silver cross-wire-   40 Transparent substrate-   42 First supporting side (of transparent substrate)-   44 Opposing second supporting side (or transparent substrate)-   50 Transparent region(s)-   60 Non-exposed and non-developed silver halide grains-   62 Silver metal particles-   64 Hydrophilic binder-   100 Conductive film element precursor provided-   105 Conductive film element precursor imagewise exposed-   107 Imagewise exposure of first side of conductive film element    precursor-   109 Imagewise exposure of second side of conductive film element    precursor-   110 Exposed conductive film element developed-   112 Development of first side of imagewise exposed precursor-   114 Development of second side of imagewise exposed precursor-   D1 Silver micro-wire maximum height-   D2 Silver micro-wire minimum height-   L Silver micro-wire length-   S1 Distance between adjacent silver main wires-   S2 Distance between adjacent silver micro-wires-   W Silver micro-wire width

The invention claimed is:
 1. An electrically-conductive articlecomprising a transparent substrate having a first supporting side and anopposing second supporting side, the first supporting side comprising:an electrically-conductive silver connector wire pattern, andoptionally, transparent regions outside of the electrically-conductivesilver connector wire pattern, wherein: (i) the electrically-conductivesilver connector wire pattern comprises at least one silver main wirethat comprises two or more silver micro-wires that are electricallyconnected to a silver end wire at an end of the at least one silver mainwire, the two or more silver micro-wires and the silver end wire in theleast one silver main wire forming a bundled pattern; (ii) the averagelength of each silver micro-wire is at least 1 mm; (iii) the ratio ofthe average width of each silver micro-wire to the average distancebetween two adjacent silver micro-wires in each bundled pattern is atleast 0.5:1 but less than 2:1; (iv) the electrically-conductive silverconnector wire pattern has an integrated transmittance of less than 68%;and (v) for each silver micro-wire, the ratio of maximum height tominimum height is at least 1.05:1.
 2. The electrically-conductivearticle of claim 1, wherein for each silver micro-wire, the ratio ofmaximum height to minimum height is at least 1.1:1.
 3. Theelectrically-conductive article of claim 1, wherein at least one silvermicro-wire has a maximum height that is its center height.
 4. Theelectrically-conductive article of claim 1, wherein at least one silvermicro-wire has a maximum height that is closer to its outer edge than toits center.
 5. The electrically-conductive article of claim 1, whereinthe average width of each silver micro-wire is at least 5 μm and up toand including 20 μm.
 6. The electrically-conductive article of claim 1,wherein each bundled pattern comprises multiple silver cross-wiresbetween adjacent silver micro-wires, wherein the multiple silvercross-wires are arranged at a distance from each other of at least 100μm.
 7. The electrically-conductive article of claim 1, wherein eachbundled pattern comprises multiple silver cross-wires in a set ofadjacent silver micro-wires that are offset from multiple silvercross-wires in another set of adjacent silver micro-wires.
 8. Theelectrically-conductive article of claim 1, wherein the at least onesilver main wire comprises from two to ten silver micro-wires in abundled pattern.
 9. The electrically-conductive article of claim 1,wherein the average distance between any two adjacent silver main wiresis greater than the average distance between any two adjacent silvermicro-wires in each bundled pattern by at least 30%.
 10. Theelectrically-conductive article of claim 1, wherein the ratio of theaverage width of each silver micro-wire to the average distance betweentwo adjacent silver micro-wires in each bundled pattern is at least 1:1and up to and including 2:1.
 11. The electrically-conductive article ofclaim 1, wherein the electrically-conductive silver connector wirepattern has an integrated transmittance of less than 50%.
 12. A touchscreen device comprising the electrically-conductive article of claim 1.13. The electrically-conductive article of claim 1, wherein theelectrically-conductive silver connector wire pattern comprises at leasttwo adjacent silver main wires, and the average distance between the atleast two adjacent silver main wires is greater than the averagedistance between any two adjacent silver micro-wires in each bundledpattern.
 14. The electrically-conductive article of claim 13, whereinthe average distance between any two adjacent silver micro-wires in eachbundled pattern is at least 2 μm and up to and including 10 μm.
 15. Theelectrically-conductive article of claim 1, wherein each bundled patterncomprises at least one silver cross-wire between adjacent silvermicro-wires that is not at the end of the adjacent silver micro-wires.16. The electrically-conductive article of claim 15, wherein each of themultiple silver cross-wires is substantially perpendicular to theadjacent silver micro-wires.
 17. The electrically-conductive article ofclaim 1, further comprising on the opposing second supporting side ofthe transparent substrate: an opposing electrically-conductive silverconnector wire pattern, and optionally, transparent regions outside ofthe opposing electrically-conductive silver connector wire pattern,wherein, on the opposing second supporting side of the transparentsubstrate: (i) the opposing electrically-conductive silver connectorwire pattern comprises at least one silver main wire that comprises twoor more silver micro-wires that are electrically connected to a silverend wire at an end of the at least one silver main wire, the two or moresilver micro-wires and the silver end wire in the at least one silvermain wire forming a bundled pattern; (ii) the average length of eachsilver micro-wire is at least 1 mm; (iii) the ratio of the average widthof each silver micro-wire to the average distance between two adjacentsilver micro-wires in each bundled pattern is at least 0.5:1 but lessthan 2:1; (iv) the opposing electrically-conductive silver connectorwire pattern has an integrated transmittance of less than 68%; and (v)for each silver micro-wire, the ratio of maximum height to minimumheight is at least 1.05:1.
 18. A touch screen device comprising theelectrically-conductive article of claim
 17. 19. Theelectrically-conductive article of claim 17, wherein the opposingelectrically-conductive silver connector wire pattern comprises at leasttwo adjacent silver main wires, and the average distance between theseat least two adjacent silver main wires is greater than the averagedistance between any two adjacent silver micro-wires in each bundledpattern.
 20. The electrically-conductive article of claim 19, whereinthe average distance between any two adjacent silver micro-wires in eachbundled pattern on the opposing second supporting side of thetransparent substrate is at least 2 μm and up to and including 10 μm.